does the 2.8l AFC engine have such a beast. These pumps deilver fresh air into the exhaust on warm up because of the rich mixture upon start up. I am wondering if this baby, if it indeed exists on our engines, may not be responsible for our cold start rattling?

is utilized to reduce NOX emissions of an engine. In fact, I don't recall seeing an air injection pump on either my previous Audi cars (4000S 5+5 and 5000S).

I believe some of the earlier engines did have air pumps. If you look (standing in front of the car) on the back of the left side cylinder head you will see a metal plate screwed to the head. This is a block off plate where the air pump used to be.